Put everything into a clean Mason or ceramic jar, making
sure the water covers the rinds generously (add more water if it doesn't).

Cover with a cloth and keep in a warm corner of the
kitchen. It will smell strong after a day or so, but keep stirring the rinds
down under the water and all will be well. You should see fermentation in a day
or so. Ferment for a week, stirring often to discourage mold, then strain,
chill, and serve right away.

I would estimate that the guarapo has 4-6% abv, but then
again, who ever took out a hydrometer in those days?